$f(t) = 5t-7$ $f\Big($
Explanation: We need to solve an equation with the function's formula $5t-7$ on one side and the given output $48$ on the other side. $\begin{aligned} 5t-7&=48\\\\ 5t&=55\\\\ t&=11\end{aligned}$ Therefore, $f(11)=48$.